I think it should be satin finish. Gloss could cause a glare on a dash.

X2

Although it might not be as much of an issue with black as it would be with other colors.

Personally I have had very good luck with the SEM products.

1957 Plymouth (Hemi, Dual Quads, A833 4 Speed 9 1/4 w 4.10) Sold
1937 Dodge Pickup (Hemi, 6X2 intake, 46RH, Dana 60 w 4.56) Sold
1968 Plymouth Valiant 2dr sedan (354 HEMI, 46RH w/4.30 gears) under construction